Abstract
OBJECTIVE: To estimate endophthalmitis incidence after cataract surgery nationally and at the state level in 2003 and 2004 and to explore risk factors. DESIGN: Analysis of Medicare beneficiary claims data. PARTICIPANTS: We evaluated billed claims for cataract surgery and endophthalmitis diagnosis and treatment for all Medicare fee-for-service beneficiaries in 2003-2004. METHODS: Cataract surgeries were identified by procedure codes and merged with demographic information. Cataract annual surgical volume was calculated for all surgeons. Presumed postoperative endophthalmitis cases were identified by International Classification of Diseases-9 Clinical Modification Codes on claims within 42 days after surgery. Endophthalmitis rates and 95% confidence intervals (CI) were calculated at state and national levels. Logistic regression was used to investigate the association between developing endophthalmitis and surgery location and surgeon factors. MAIN OUTCOME MEASURES: Endophthalmitis incidence and risk factors. RESULTS: We included 4006 cases of presumed endophthalmitis, which occurred after 3 280 966 cataract surgeries. The national rate in 2003 was 1.33 per 1000 surgeries (95% CI, 1.27-1.38) and decreased to 1.11 per 1000 (95% CI, 1.06-1.16) in 2004. Males (relative risk [RR], 1.23; 95% CI, 1.15-1.31), older individuals (RR, 1.53; 95% CI, 1.38-1.69; ≥85 compared with 65-74 years), blacks (RR, 1.17; 95% CI, 1.03-1.33), and Native Americans (RR, 1.72; 95% CI, 1.07-2.77) had increased risk of disease. After adjustment, surgeries by surgeons with low annual volume (RR, 3.80; 95% CI, 3.13-4.61 for 1-50 compared with ≥1001 annual surgeries) and less experience (RR, 1.41; 95% CI, 1.25-1.59 for 1-10 compared with ≥30 years), and surgeries performed in 2003 (RR, 1.20; 95% CI, 1.13-1.28) had increased endophthalmitis risk. CONCLUSIONS: Endophthalmitis rates are lower than previous yearly US estimates, but remain higher than rates reported from a series of studies from Sweden; patient factors or methodologic differences may contribute to differences across countries. Patient age, gender, and race, and surgeon volume and years of experience are important risk factors.